Sunday, January 13, 2008

Riding the Wave

After our Thanksgiving travel experiences, Husband and I were watching the weather very closely for our Christmas trip down to North Carolina. After a weekend of clouds and rain, we were happy to see a clear forecast for Christmas Eve. Our plan was to take advantage of the nice weather and have a little fun on the way down to my parents. We knew there was a pretty stiff headwind forecast-- but figured that we'd still be able to get in a few stops along the way. The winds on the ground looked reasonable-- and seemed to be up and down the runway all along our route. W24, LYH, W90, and 0V4 are all within a few miles of each other, so our plan was to hit as many of these as possible before we got to our bingo time and needed to leave the area so we could make the Christmas Eve service with my parents.

Isn't it funny how most flying blogs start with something along the lines of, "the plan was to..." but rarely finish with completing that plan?!

After a good workout at the gym and a final check of all our gear, we loaded up and set out. By now, the winds were forecast for around 50 knots at altitude. We double checked with our flight instructor as we preflighted and decided that even though our progress would be significantly slower than desired, it would be fine to fly. We took off and started down to our first stop, W24. We could tell the winds were crazy soon after we were air born. The turbulence below the Bravo shelves was intense. So we were happy to leave the Bravo airspace behind us and climb up to our cruise altitude.

Our route took us right down the edge of the foothills of Virgina. While West Virginia is very mountainous (though someone from Colorado might not see it that way!), where Virginia and West Virginia come together is right where the mountains start to break up. From our perch, we could see flatlands over to our left (the East), and we could see the very straight long ridges to our right (the West), and below us was a mixture of both, showing up in scattered peaks and smaller hills. Flying along, Husband set the autopilot and we admired the view. A few times along the way though, we noticed a strange occurrence. We would start to lose airspeed-- and occasionally altitude. At the same time, our RPMs would decay. The autopilot would keep fighting it, and that seemed to make the situation worse. We discussed the possibilities. Was this some form of mountain wave activity? Was there something wrong with the airplane? We talked about landing, but every time we got really worried, the problem seemed to get better. So we tried flying a little further away from the hills... but how far was far enough?

We were thankful to see that our first destination was approaching-- but as we started our descent, the turbulence became intense. Given how we were getting bounced around, we decided maybe it wasn't the day to get a bunch of stamps in our aviation passports. After considering our various options, and realizing that we would need to land and refuel somewhere, we decided that we should cut our losses and land at Lynchburg. We'd at least get one stamp, check for the updated weather, and regroup. So, we called Tower and set up to land. Once on the ground, we ended up at Falwell Aviation-- the newest FBO on the field.

Falwell Aviation is run by a couple of brothers. One of them happened to be there when we walked into the FBO and offered to give us a tour. It was really interesting. He and his brother also own a airport W24-- the airport we were going to land at before we decided to come on to LYH. Apparently their family had owned a trucking business a long time ago. They put in a runway at their family farm, and started to use planes to ship some of the materials by air. Over time, that grew into an airport used as an alternate for the factories and airlines using LYH. Now, the family owns the airport, a flight school, and a whole fleet of airplanes. Pretty cool. You never know what you're going to find at an airport!

Back to the flying tale. After fueling up and checking the weather, we got ready to depart. On our runup, we noticed some strange fluctuations in the RPM. We were pretty confused at first-- but realized that we were doing the runup with our nose not facing into the wind. Oh yeah! That's right, M always taught us to face into the wind to do the runup. Hmmm. Maybe this is why. :) So we turned the nose into the wind, and tried it again. Yep. That did it. Things seemed fine. Quick call to Tower and we were on our way again. This time with me flying. We got off the runway and were about 10 miles off the airport, when the problem started again. This time, the drop in RPM, airspeed, and altitude was even more pronounced-- we lost our ability to climb. Unsure of what the issue was-- or the best way to deal with it, we told the controller we had just been handed off to that we were experiencing difficulty holding our climb and our altitude, and that we wanted to return to the airport. We both looked at each other at this point. We couldn't believe we were having to make a "return to airport" call. We were transferred back to Tower and told them what was going on. Another plane (I think maybe a commuter plane) was also approaching, but the controller had them extend their downwind a bit so we could come on in. We landed without issue and went back to Falwell. On the ground, we decided to give our instructor a call. We ended up talking to a few instructors-- and all agreed that based on the conditions we were seeing and our location, we were experiencing mountain waves. They gave us a few pointers on dealing with it-- to try and ride the wave, using power to keep us somewhat stable. We decided to give it one more shot. So after a quick text message to my parents, we called Tower and departed LYH. In the air, we found that by adding power as the RPM or airspeed started to decay, we could keep the altitude from decaying. It was definitely more work than usual, but we were able to feel confident in our ability to keep the plane flying and somewhat stable. As we continued south, the wave activity decreased, and things got easier. We landed safely in Morganton as the sun was getting low in the sky. Dad and Flyer were there waiting for us. We were pretty happy to see Flyer bound across toward us when we got out of the plane (the airport was empty).

Some lessons learned:
  • Mountain wave isn't just about sudden and violent drops, it can show up in other forms
  • If it's gusty or high winds, it really matters if you keep your nose pointed into the wind
  • ATC is really great about helping you out
  • Your flight instructor can be a great source of information even after you get your license-- it's in their best interest to help keep you safe... but you have to let them know if you need help
  • High winds at altitude can impact performance in some surprising ways-- it may feel smooth, but anytime there's something unusual in the flying conditions, you should keep an extra eye on things

1 comment:

Teller said...

I experienced this type of long wave mountain wave, myself, out in California/Arizona (Banning Pass near Palm Springs is the worst). More than 50-60 miles from the range, we could go in about three minute cycles at full nose down trim, full forward pressure, idle power, and still climbing to prop/throttles full forward, full aft trim, holding Vy then Vx and still descending. After a while we ended up having to get a 2,000 foot block altitude clearance (we were IFR) because we couldn't stay within 500 feet of our assigned altitude, let alone the required 100 feet. It's a trip, isn't it!

Glad to see y'all handled this bizarre phenomena so well...isn't ATC assistance great! Hopefully conditions improve for y'all's next time up!